[ARC5] Why "Noodling" About Sweep Tubes

[Fuqua, Bill L]

  One other thing, when using these tubes you are allowed to let the plate glow.
Looks great in an amplifier.
   If you use a 4-125A you can later on upgrade to 4-240A, 4-400A or 3-500z (if G-G amp) by
using larger filament transformer and higher current power supply, you may have to change
the input and output ckts depending on design. If you use continuously variable designs using 
roller inductors and they are conservatively rated no change needed . Sockets are all the same.

73
Bill wa4lav

________________________________________
From: arc5-bounces at mailman.qth.net [arc5-bounces at mailman.qth.net] on behalf of Fuqua, Bill L [wlfuqu00 at uky.edu]
Sent: Tuesday, October 22, 2013 2:19 PM
To: Dennis Monticelli; Robert Eleazer
Cc: ARC-5 Maillist
Subject: Re: [ARC5] Why "Noodling" About Sweep Tubes

  Common tubes that are rather inexpensive are 4-125A and 4E27A tubes.
Lots were manufactured and floating around out there but very very few applications.
  If you look on ebay at the "Sold Prices" for these tube not the listed prices you will see that
they sell from $7 to an extreme of $20, but mostly around $10 or $12 each.
  These are great tube to build amplifiers from, much better than 813's which are more popular.
The 4E27A will fit in a 813 socket. So, why use a sweep tube when you can get good
cheap transmuting tubes.

73
Bill wa4lav

________________________________________
From: arc5-bounces at mailman.qth.net [arc5-bounces at mailman.qth.net] on behalf of Dennis Monticelli [dennis.monticelli at gmail.com]
Sent: Tuesday, October 22, 2013 12:53 PM
To: Robert Eleazer
Cc: ARC-5 Maillist
Subject: Re: [ARC5] Why "Noodling" About Sweep Tubes

You may wish to consider connecting a beam power tube as a triode and
trying it in the application.  As noted previously the 6DQ6 is a
lightweight; indeed all sweep tubes are deficient in plate dissipation.
 They have a lot of cathode and can handle the peaks, but not the high
average.  The 6146B variants are better of course.

You should be able to find useful curves for triode-connected beam power
tubes among the audiophile documentation.

Dennis AE6C


On Tue, Oct 22, 2013 at 7:04 AM, Robert Eleazer <releazer at earthlink.net>wrote:

> Dave:
>
> I have a 12DQ6B, acquired for reasons that currently escape me.  Looks
> like it is NOS NIB.  Maybe I bought it in a lot of tubes, not sure.  I am
> pretty sure the 6DQ6B is a widely used sweep tube.  You are welcome to the
> 12DQ6B if you wish.
>
> I also have a couple of 6GE5's.  I believe these are sweep tubes and I
> know I acquired these for use in some future project; I think either a
> crystal controlled Galaxy transceiver or an HW-18.  I recall they were
> pretty cheap.
>
> Also, I recently bought a sleeve of five 6883B's.  They are 12 Volt
> 6146B's.  I plan to use them in a TS-520 I am repairing and also possibly
> in a HW-100.  They appear to be NOS NIB and cost me a total of $20 plus
> shipping, a total of less than $30.  Don't know if they are adaptable for
> the BC-375 but they are available on ebay, occasionally for astonishingly
> low prices.  The 6159, the 24 volt 6146, is available also; I got a pair
> for $10.
>
> Wayne
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